What does the transitional phrase “comprising” mean in a patent claim?

The transitional phrase “comprising” in a patent claim is inclusive and open-ended. According to the MPEP, The transitional term “comprising”, which is synonymous with “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

This means that a claim using “comprising” allows for the inclusion of additional elements or steps beyond those explicitly stated in the claim. For example, a claim for a device “comprising A, B, and C” would cover devices that include A, B, and C, as well as devices that include A, B, C, and additional elements.

To learn more:

• comprising
• open-ended claims
• inclusive language
• patent drafting